nik chmiel wrote:
I interpret this to mean that a thick uniform absorption filter on the sensor would introduce not just reflections but also focus shifts with angle of incidence, so all else being equal the image would look progressively out of focus towards the edges even though the focus point was correct - am I right with this?
Nik
Nik:
Have you ever seen the edges of a 5D frame shot with their wides such as a 17-40mm? They look quite out of focus and I don't think it is all the lens' fault.
Here is a M8 shot done before the sun rose, using a $350, 15mm Voitlander lens. In the full frame shot, I cropped it slightly to correct for a tilted horizon. The lower left corner crop is from whe whole file. I have not seen a wide angle (20mm or less, exotics included) shot on the 5d, this sharp in the corner.
The Zeiss 21 illustrates that there is no inherent resolution problem at the corners of the 5D frame. It can stay pretty crisp right to the corner. Lots of other lenses illustrate this as well. I think the Canon 17-40 is just a victim of the difficult problems of making near perfect wideangles.
...and by the way don't forget that we are looking at you M lens at the corner of a smaller area. The Canon 17-40 does pretty well on a 1.3 crop. It's the full frame corners that struggle. The Leica 21-35 isn't too hot in the corners on full frame.
brainiac wrote:
The Zeiss 21 illustrates that there is no inherent resolution problem at the corners of the 5D frame. It can stay pretty crisp right to the corner. Lots of other lenses illustrate this as well. I think the Canon 17-40 is just a victim of the difficult problems of making near perfect wideangles.
That is greater than 20mm BTW, the 15mm was shot at f5.6.
I was talking 20mm and under, so we need to talk 19mm in the Leica which is excellent.
You should post a Zeis 21mm on the 5D corner crop to see what it does. Shoot is at f5.6 or f8 to be fair to the 15mm shot I just posted.
I bet you could buy a M8 and a Voitlander 15mm for less than a Zeiss 21mm, adapter and 5d costs.
Granted for the money the 15 is terrific. But it is a 20mm on M8.
> ...Have you ever seen the edges of a 5D frame shot with their wides such as a 17-40mm? They look quite out of focus and I don't think it is all the lens' fault.
I only raised the spectre of the mourned 21 because it illustrates that there is nothing intrinsically wrong with the 5D's corners and wideangle.
Didn't Guy already do that? The three landscape shots linked to on page 126: https://www.fredmiranda.com/forum/topic/470256/125 are with the 21. They are unsharpened of course, so you will want to apply an unsharp mask before they look as good as a raw M8 file. ;-)
Btw, can't you buy eight or more Voitlander 15mm new for what a used Zeiss 21mm goes for?
Where I live a new 5D and a used Zeiss 21 cost about the same as a new M8 and a used CV15. I am budgeting about 1600 UK pounds for the 21.
Edited to add link to page 126
Edited by brainiac on Dec 19, 2006 at 04:04 PM GMT
brainiac wrote:
I don't think that is right Nik, no. The parallel faces of the filter introduce no variable focus shift across the frame, they simply lengthen the path by a small but exactly matching amount across the whole frame. That's because the refraction as the light exits the filter exactly undoes the bend that happened as the light came in.
Look up Snell's law - refraction depends upon angle of incidence as well as RI. Light striking the corner at an IR interface (such as air-glass) will be refracted more than closer to the optical axis. There is no refraction, but there is RI magnifcation on-axis.
Tom
Corner resolution on the M8 is excellent with most samples I have seen posted. Sure it's a crop camera, but try getting the same performance with even a 1D MKII and Canon lenses on the wide end. The M8 and lenses are overpriced for many users, and the M8 has more issues than it should, but it still is a combination that can produce excellent results. Comparable to any DSLR. It all depends on what flavor you want.
Acutance can be very helpful in upsizing a file for a large print. Better than a file with halos and poor edge detail. One makes the print look snappy, the other makes it look a little muddy. Few people take a loupe to a large print to judge its "resolution" (which is analguous to what you are doing looking at them on your monitor at >100%).
> The M8... ...is a combination that can produce excellent results.
Agreed
> Comparable to any DSLR.
That's what we don't yet know, except in so far as my JPEG test goes.
> Acutance can be very helpful in upsizing a file for a large print.
I'm guessing, but presumably acutance is better added AFTER upsizing, not before. That way the sharpness is finer and looks less like those oversharpened press shots.
> Few people take a loupe to a large print to judge its "resolution" (which is analguous to what you are doing looking at them on your monitor at >100%).
...and analogous to what you are doing when you (a) make a very large print or (b) make a print from a crop or (c) are coping with difficult subject matter like a large wedding group.
Guy Mancuso wrote:
Good than go do it and proof it to yourself than wasting 250 pages of facts you can't accept or peoples opinions. Hmmm by the way why did you even bother to post here if you want to proof it yourself and not come on the web and hear peoples opinions. Fact is that is exactly why your here is listen to peoples opinions but your just too damn stubborn to accept them. So get off the web and go proof it. Stop wasting the bandwidth and peoples opinions.
Guy, I recall you had a 5D as a back-up for a DMR a while ago. So you have seen the results using the same lens on different bodies - I guess you could just as easily say 'been there done that' ;->> since you got rid of the 5D.
If one has deep enough pockets one could buy all the systems and do one's own comparison - based on prints of course!
Tom
Guy Mancuso wrote:
Good than go do it and proof it to yourself than wasting 250 pages of facts you can't accept or peoples opinions. Hmmm by the way why did you even bother to post here if you want to proof it yourself and not come on the web and hear peoples opinions. Fact is that is exactly why your here is listen to peoples opinions but your just too damn stubborn to accept them. So get off the web and go proof it. Stop wasting the bandwidth and peoples opinions. there seems no shortage of opinions but little in the way of demonstatable facts in this thread - all questions are valid to whoever is interested until we see some accceptable comparisons.
brainiac wrote:
Didn't Guy already do that? The three landscape shots linked to on page 126: https://www.fredmiranda.com/forum/topic/470256/125 are with the 21. They are unsharpened of course, so you will want to apply an unsharp mask before they look as good as a raw M8 file. ;-)
Where I live a new 5D and a used Zeiss 21 cost about the same as a new M8 and a used CV15. I am budgeting about 1600 UK pounds for the 21.
Edited to add link to page 126
Edited by brainiac on Dec 19, 2006 at 04:04 PM GMT
Richard:
I opened up the full rez file, applied usm as suggested, but the usm had little effect becuase the corners are so soft. It did sharpen up the rest of the file though.
Here is the picture I uses, as it had detail in the corners.
As I don't have an M8 I cannot therefore offer any 'facts' as to how it compares resolution wise to the 5D/1ds2. From the samples I have downloaded and processed from the M8 I have the 'opinion' that it produces images of a very high order indeed. Similarly from your own expert descriptions of the image quality anyone would be seriously misinformed or wilfully ignorant to take a contrary position. However it seems to me (my opinion that is) that Richard and others are totaly legitimate in asking for a simple (or sophisticated) side by side comparison with another camera system to resolve (sorry) the resolution issue. Additionaly few if anyone is saying the M8 produces substandard, inferior or inadequate images whatsoever. I have no intention of purchasing an M8 but that decision has nothing to do with image quality. I do however has a professional interest in the image quality of the M8 as part of my job involves post production and RAW processing of other photographers images and in the not too distant future I expect to be dealing with M8 files. I hope this clarifies my position and justifies my participation on this subject.
Richard, if you can really buy the Zeiss 21 Distagon for Ł1600, then I suspect you could make a living just buying them up and re-selling them in the States. Recent prices are higher, I think. Have you seen one for sale recently? It is not really relevant anyway, just curious.
Guy, don't get all upset again. There are plenty of worse people around than Richard. He is just particularly hard to convince, which he certainly has a right to be. You two seem to have gotten off on the wrong foot, for some reason. Don't take anything personally here. It is just a forum of strangers, and it is too easy to read the wrong tone of voice into a post.
BTW, the 15mm was shot at f5.6.